On Sun,11/6/2016 11:06 AM, Ron D'Eau Claire wrote:
Sri Jim: You must have misunderstood. You defined the rig as the 'load' so I
used your definition. Perhaps that's the problem.
I think you misunderstood me. ) The rig is the load for the line ONLY
when the line is feeding the RECEIVER. Loss
On 11/6/2016 11:06 AM, Ron D'Eau Claire wrote:
Sri Jim: You must have misunderstood. You defined the rig as the 'load' so I
used your definition. Perhaps that's the problem.
I thought that too. Jim was here for dinner last night but I forgot to
ask him.
You are right; the antenna is
Sri Jim: You must have misunderstood. You defined the rig as the 'load' so I
used your definition. Perhaps that's the problem.
Avoiding that terminology, if there is no reflected power at the rig, the
SWR will be 1:1. Power can be "lost" in the antenna (hopefully radiated) or
consumed in the
Line loss decreases the SWR measured at the source, not the load.
In this case, thinking in terms of return loss makes this thought experiment
easier. The line loss adds to the return loss of the load, increasing the input
return loss by a factor of 2 X line loss (dB). Higher return loss =
On Sat,11/5/2016 12:57 PM, Ron D'Eau Claire wrote:
...The SWR on a line is determined entirely by the match between the line
and the load -- when we're transmitting, that's the antenna, and when we're
receiving, it's the receiver. And yes, it's same everywhere along the line
as long as the line
...The SWR on a line is determined entirely by the match between the line
and the load -- when we're transmitting, that's the antenna, and when we're
receiving, it's the receiver. And yes, it's same everywhere along the line
as long as the line is uniform -- that is, the same impedance, and with
Yes, and that is exactly the right way to understand it -- when an
antenna is unbalanced, regardless of the reason for the imbalance, the
feedline becomes part of the antenna unless it is choked. Indeed, that's
the major reason to use a good choke -- to prevent noise picked up on
the outside
together eliminates
another variable.
73, Ron AC7AC
-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Alan
Bloom
Sent: Friday, November 4, 2016 11:03 PM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] TxMon and K3 (tuner bypassed) SWR
You are talking about SWR as if it were something real and physical that
could damage the transmitter's finals. It's not - it's just a mathematical
construct that makes it easier to calculate various other quantities (such
as loss in the transmission line). The real physical quantities that can
Thanks for replies
I will borrow a Bird meter to see what it say but I think in this
case the error is in the K3 and not the P3. as one mentioned a
reading of 1:1,1 vers 1:1,2 is neglegable but this is a error by a
whole number 1:1 vs 1:2
My concern is that if its really a 1:3.5
The SWR is the same anywhere on the feedline, assuming the loss is low.
If changing the feedline length a few feet causes a significant change
in SWR reading, then either the directional coupler in the SWR meter
isn't doing a good job, or (more likely) there is feedline radiation.
In the
It also depends on the line loss per unit length. A high-loss feedline
will be more forgiving as measured, but less energy is transferred to
the load. If a line is very low-loss per length, you can tune out the
reactance or mismatch (by transformation or direct compensation) without
losing
I have always understood that the SWR on a line will be almost the same
wherever it is measured (it will increase slightly as you approach the
load due to losses). It is the impedance of the load as transformed by
the line that changes.
One thing that I've noticed is that SWR meters often
How much coax is between the K3 and P3 monitor? Only a few feet will create
a growing error as the SWR increases, since the standing waves on the
coaxial line produce different readings at different points along the line.
If you want to compare the SWR meters in the K3 and P3, be sure the P3
On 11/4/2016 3:59 PM, dm...@nexicom.net wrote:
I recently installed the TX monitor in my P3 and have a discrepancy with
the SWR reading between it and the K3
with a dummy load connected the P3 and K3 read 1.12 and 1.0
respectively a level of error that is to me quite acceptable.
however
David,
You are trying to compare apples and oranges and expecting them to be
the same.
The K3 SWR indication is at the *input* to the KAT3, and the TX Monitor
is indicating the SWR at the *output* of the KAT3.
That is no reason that they should match.
The TX Monitor will always give you
I recently installed the TX monitor in my P3 and have a discrepancy
with the SWR reading between it and the K3
with a dummy load connected the P3 and K3 read 1.12 and 1.0
respectively a level of error that is to me quite acceptable.
however when connected to an antenna I will see the
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